Telemarketing is an important and rapidly growing segment of the telecommunication industry. Using ISDN signaling as defined by ISDN standard Q.931, telecommunication systems functioning as telemarketing systems (such as the AT&T Definity Telecommunication System) provide many useful features that enhance the service provided to customers. A telemarketing agent who uses a modern telemarketing terminal that has combined voice and data capabilities is not only provided a voice connection but also a wealth of data displayed on the terminal from a centralized database.
Prior art telemarketing systems have only been able to provide combined voice and data features to telemarketing terminals which are co-located with the telemarketing system or which are connected to the telemarketing system via dedicated lines. These two constraints have resulted in the necessity of grouping telemarketing agents in dedicated office facilities. Since the telemarketing agents must leave their homes, this grouping means that the agents in general must work full time.
For telemarketing services for airline reservations, retail marketing for large companies, or information lines for large companies, the requirement that telemarketing agents be grouped in the same physical location and working full time is not only acceptable but probably desirable from a many points of view such as supervision and morale. However, there are telemarketing services that only require telemarketing agents for a few hours each day. One such service is responding to calls resulting from a television commercial. In addition, there are many people in our society today who want to work on a part time basis at home. Many of these people are highly qualified to function as telemarketing agents. The problem has been in being able to provide telemarketing terminals to these people at home that have the same capabilities as telemarketing terminal provided to grouped telemarketing agents. This problem is a communication problem resulting from the manner in which the public telephone system functions. Nor does ISDN signaling as defined by the ISDN standard solve this problem for reasons outlined in the following paragraphs.
ISDN signaling is intended to provide an international standard to control the initialization of calls, maintenance of calls, termination of calls, communication of national use information, local serving network information, and user-specific information for telecommunications systems and terminals. The ISDN standard defines two standard links: (1) primary rate interface (PRI) links, each having 23 data channels (B channels) and one signaling channel (D channel), and (2) basic rate interface (BRI) links, each having two B channels and one D channel.
The ISDN message format allows each message to have a number of information elements (IEs) and groups IEs by codesets. There are eight possible codesets, numbered 0-7. Codeset 0 is the currently defined set of information elements for call control and includes IEs that control the initialization, maintenance, and termination of calls. Codesets 1-4 are reserved for future ISDN standard Q.931 expansion. Codeset 5 is for national use; codeset 6 is for IEs specific to the local serving network; and codeset 7 is for user-specific IEs.
In a system having a plurality of switching nodes, the problem with ISDN signaling is that each intervening switching node in the signaling path must process messages that communicate the signaling information because each intervening switching node terminates the signaling channel. Because of this message processing, the following three major problems are created.
First, each intervening switching node processes and interprets all IEs (codeset 0) relating to the control of initiation, progress, and termination of calls. The result is that a telemarketing terminal cannot be remotely connected to a controlling switching node through intervening switching nodes using standard links if standard signaling is used for call control. Telemarketing terminals can only be remotely connected if non-standard signaling is used for call control or if dedicated links are used. However, non-standard signaling requires that both the controlling switching node and the controlled telemarketing terminal function differently than if the controlled telemarketing terminal is directly connected to the controlling switching node.
The second problem is that if standard signaling is used, the transmission rate of signaling information is greatly reduced because of the need to process that information in each intervening switching node.
And thirdly, a large additional processing load is placed on the intervening switching nodes.
As previously described, the ISDN standard is intended for a telemarketing terminal to be directly controlled via the signaling channel by the local switching node to which the telemarketing terminal is attached since any intervening switching node processes and interprets all IEs performing call control. Hence, the ISDN standard is adequate for most types of telecommunications applications. Nonetheless, this standard suffers from serious problems when it is desirable to remote a telemarketing terminal from a controlling switching node through another switching node such as a public network. In order to implement such remote applications, the remote telemarketing terminal must function in a different manner if ISDN call control signaling is not used, or dedicated links must be used if ISDN call control signaling is used.
The most disadvantageous result of not being able to use standard signaling without dedicated links is that the remote telemarketing terminal cannot be utilized in the same manner as a telemarketing terminal directly connected to the controlling switching node. Whereas telemarketing demonstrates the need for remote equipment, there are many other applications where it is desirable to remote terminal equipment from the controlling switching node and to allow that equipment to have the same capabilities as if it were directly connected to the controlling switching node. For example, when the controlling switching node is a PBX, it is desirable to control a small number of telephones at a remote location. Because of the distance involved, it is often desirable to connect this terminal equipment to the PBX via the public network. Office personnel operating procedures make it desirable for the users of the remote terminal equipment to be provided the same functions as the users of the terminal equipment directly connected to the PBX. However, for a small number of remote users, it is not economical to put a switching system at the remote location capable of terminating a PRI link and switching the channels from this link to the users.